Oh boy, where do I even begin?
Other answers to this question mentioned personal protection through clothing, repellents, etc.
There are actually other prophylaxes (plural of prophylaxis) in the form of drugs. The Center for Disease Control and Prevention (CDC) has a lot information on malaria. They are a great resource to have for those who are traveling to affected areas.
The CDC website has detailed information about the dosage and reasons to take a certain drug. It will help you decide, or get a better idea, what you are getting yourself into.
Of the list of drugs, I have only taken Doxycycline, but it was prophylaxis for something else. I took it for exposure to Francisella tularensis, or tularemia. I work in a hospital lab, so coming across strange organisms is no surprise. In fact, I took Doxycycline due to having a reaction to Ciprofloxacin. As you can see, drugs do overlap in their use cases.
Malaria is serious business. You don't want to end up having it and end up in crisis. Several weeks ago, I came across a patient who had Plasmodium in his blood. He was an outpatient, which required the hospital to call him back. He was in crisis days later with 5% parasitemia in his blood. That may sound like a small number, but it was life-threatening.
Here's an example from CDC website of what I would have saw in the patient's blood smear.
The medical director had to work with CDC to use Artesunate to treat this patient. That is how serious the case was. You can read more about the drug on the CDC website.
Dengue, is a bit less exciting because there was not much you can do about it for the longest time. There have been recent developments as I checked the CDC website. Here is what I found:
Two months ago, FDA approved Dengvaxia® for children in US territories. There are two things I want to point out in that page: WHO's statement and the manufacturer's warning.
They go hand in hand. This is due to antibody enhanced infection, which makes Dengue unique. In short, your body produces antibody against a disease as it "remembers". In the case of Dengue, the antibody can facilitate infection of another serotype of the virus.
I have done Dengue research in my university years and that was the hurdle for many researchers. Developing a vaccine that didn't make subsequent exposures worse was the main challenge. It did not help it was not a hot topic like HIV, etc. either.
It is somewhat counter intuitive, but this vaccine is for people who have had exposure to Dengue in the past. But, it is awesome to see that there have been significant developments in this area.
Now, stay safe out there!
Vaccines are available for few disease like malaria but I don't think some preventive medicine for dengue is available.
However, you can take some preventive measures to avoid these disease. Some of the precautions are:
1. Avoid mosquito bite as much as possible.
2. Wear full sleeves cloths especially when going out.
3. Use Mosquito repellent lotion.
4. Spray incest killer spray in your house.
5. Avoid going out in evening etc.
Hi, there's definitely anti malarial drugs readily available if you are in the Malaria infested or malaria prone regions.
For someone moving to a Malaria prone area, i definitely would recommend taking the anti malarial meds dosage at least a few days or a week prior to the visit. If the meds are not easily accessible then i'd recommend they start the dosage soon as they arrive.
i am not sure if anti Dengue meds are available, i think there in No.
Most important ways of prevention from both diseases would be to employ all measures to avoid mosquito bites. Personal protection and environmental protection are key. These are way more important in the long run than taking the anti malarial meds.